✓ Two crowns ✓ Same mass, different density ✓ Vertical slider ✓ Slider works ✓ Slider controls crowns — Slider direction correct ✓ Full slider range ✓ Fall animation ✓ Water displacement ✓ Rising water level ✓ Splash effects ✓ Physics correct ✓ Live mass value ✓ Live volume value ✓ Live density value ✓ Live displaced water ✓ Gilded displaces more ✓ Heureka animation ✓ No external deps ✓ Light bg / dark text ✓ Self-contained HTML
Slider direction is inverted (label says "▲ Luft / ▼ Wasser" but HTML range with writing-mode:vertical-lr + direction:rtl maps min=0/top to air and max=100/bottom to water correctly in most browsers — however the crown motion coding confirms top=air, bottom=water which is correct, yet the slider thumb physical direction is browser-dependent and may appear inverted; buoyancy unit calculation divides cm³·g/cm³·N/kg by 1000 converting grams to kg correctly, but the fake crown density of 5.5 g/cm³ is unusually low for a gilded silver alloy, though still physically defensible.
Slider direction is inverted (label says "▲ Luft / ▼ Wasser" but HTML range with writing-mode:vertical-lr + direction:rtl maps min=0/top to air and max=100/bottom to water correctly in most browsers — however the crown motion coding confirms top=air, bottom=water which is correct, yet the slider thumb physical direction is browser-dependent and may appear inverted; buoyancy unit calculation divides cm³·g/cm³·N/kg by 1000 converting grams to kg correctly, but the fake crown density of 5.5 g/cm³ is unusually low for a gilded silver alloy, though still physically defensible.